Just try sipping mug or if it doesn't work just make sure that he takes milk-based morning cereal.

Good evening,
you can try NESTLE cereals stage 2&3 with different flavors (usually it is written on the box whether you need to add milk or water). But also very good to cook oats cereal with milk by yourself and add some fruits.

Or you can try the same formula milk but another flavor (chocolate or honey).

Actually amount of sugar is the same in plain, chocolate or honey milk. And the one with honey is not recommended because it can lead to an allergy.
We switched to usual fresh goat milk after one year.